The invention relates to a fluid-conducting system with cathodic corrosion protection, having at least one device conveying and/or influencing a flow rate, in particular a pump and/or valve having at least one connection device, and having at least one device guiding a flow rate, in particular a pipe element, having connection means.
Fluid-conducting systems of this type having pumps or valves are widespread and are often used to convey and influence corrosive fluids or media, whereby the inner walls exposed to the fluid or medium sustain damage and parts of the system or of the devices have to be replaced after a certain time.
In order to protect pumps or valves against corrosion, it is known for example from South Korean patent document KR 100540390 B1 to attach a bolt connecting the casing of an valve to a water pipe to a sacrificial anode.
Pumps are also known that have sacrificial anodes arranged inside the casing. Examples for this include Japanese patent documents JP 2002295389 A, JP 2002295390 A or JP 2002242874 A.
The disadvantage with both variants lies in the fact that recurring maintenance works have to be performed and, in particular with internal sacrificial anodes, the entire system has to be switched off.
German utility patent document no. DE 7603732 U discloses a water container in the lower region of which an electric heating element is arranged. A passive anti-corrosion layer made of enamel is formed on the inner wall of the container. Furthermore, electrodes supplied with external current and providing cathodic corrosion protection are provided, wherein the electrodes can be set to an optimal potential by means of a potentiostat and a reference electrode, and at least one external current anode is arranged in the vicinity of the heating element. An arrangement of this type, however, has proven to be unsuitable for systems having a relatively high flow.
The object of the invention is to provide a fluid-conducting system or a device conveying or influencing a flow rate, having a cathodic corrosion protection system, in which the above-mentioned disadvantages are overcome, without disturbing the flow rate in the device or a pipe system connected thereto.
The object is achieved in accordance with the invention in that the fluid-conducting system comprises annular anodes, wherein an anode is arranged in each case between a first and a second connection device and/or between a first connection device and a connection means and/or between a second connection device and a connection means, the anodes are electrically connected to a monitoring arrangement by means of lines comprising one or more conductors, and the inner diameter of the anodes is equal to the inner diameter of the device guiding a flow rate and arranged on the respective anode.
According to the invention, in a further embodiment, the inner diameter of the anodes also corresponds to the inner diameter of the inflow or outflow opening, assigned to the respective anode, of the device conveying or influencing a flow rate. Turbulences and/or flow vortices in the fluid-conducting system are thus prevented.
In a further embodiment one or more threaded bores are provided in the casing, into which bores reference electrodes electrically conductively connected to the casing are screwed. It is thus possible to bring the reference electrodes into contact with the fluid or the flow rate within the casing without said electrodes protruding into the casing or without a dead space forming, i.e. a blind hole-like indentation. At the same time, this opening in the casing can be easily sealed.
The fact that the reference electrodes are arranged relative to one another in such a way that the greatest possible inner surface of the casing can be balanced in terms of the potential enables the system to be reliably operated. A state monitoring of all surfaces within the casing contacted by a medium or fluid is thus reliably ensured.
In accordance with a further embodiment, in order to optimize the operation, the monitoring arrangement comprises a control or regulation unit, a first rectifier, a second rectifier and a measuring module.
It is proposed in accordance with the invention for an annular and electrically insulating first insulation washer to be arranged between the anode and the first or the second connection device and also for an electrically insulating second insulation washer to be arranged between the anode and the connection means. It is thus possible to compensate for varying distances between the casing of the pump or the valve using insulation washers of different thickness or by using a number of insulation washers.
In order to ensure reliable insulation protection, bores are provided in accordance with the invention in the first and/or second connection device and in the connection device of the pipe elements, there being electrically insulating insulation sleeves arranged in said bores. These are preferably inserted into the bores for simple assembly.
In order to increase the insulation protection, the insulation sleeves at their free end have a collar.
The invention is also achieved by a device conveying or influencing a flow rate, in particular a pump arrangement or valve arrangement for a fluid-conducting system with cathodic corrosion protection.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.